Titler

A conversation needs a name the moment it exists. Core titles it from the first user message, and the default is the message as typed. Titler replaces that default with the words an aparte-titler model picks out of the message — 3 to 6 of them, in the message’s order, in 17 languages — inside the browser, in a few milliseconds, with a model that weighs less than an icon. Nothing leaves the page.

npm install @aparte/plugin-titler @aparte/titler-latin

import type { AparteConversationManager } from '@aparte/core';
import { loadTitler } from '@aparte/titler-latin';   // 17 European languages, 133 KB
import { setupTitler } from '@aparte/plugin-titler';

declare const manager: AparteConversationManager;    // yours — the one the chat persists to
setupTitler(manager, { titler: loadTitler });

That is the whole setup. loadTitler is called once, the first time a conversation needs a title, so the model is never on the page’s critical path; the title lands in the manager, and from there in <aparte-conversation-list> and everything else that reads it.

@aparte/core is the only peer dependency. The model is yours to pick and is not a dependency of the plugin: any object with title(message, budget?) is accepted — the runtime’s Titler, a promise of one, a loader, or a titler of your own.

The seam

The plugin is small because the seam is core’s. AparteConversationManager decides a conversation’s title in one place, on its first user message, and setTitleProvider(provider) replaces how. A provider receives the message’s text and the message, and answers a title, synchronously or not:

import type { AparteConversationManager, AparteConversationTitleProvider } from '@aparte/core';

declare const manager: AparteConversationManager;
const provider: AparteConversationTitleProvider = async (text, message) => {
    // anything: a model in the browser, a request to your backend, a heuristic
    return text.split(' ').slice(0, 5).join(' ');
};
manager.setTitleProvider(provider);          // null restores the default

An empty answer, or a throw, leaves the default title — so a titler that fails never loses the message from the sidebar. updateTitle (the user’s own rename) is untouched.

The options

The second argument is a TitlerOptions:

setupTitler(manager, {
    titler: loadTitler,   // a Titler, a Promise<Titler>, or () => Titler | Promise<Titler>
    budget: 4,            // words to keep; the model's default is 6
});

setupTitler returns a teardown that gives the manager back the provider it had — unless another was set since, which is then left alone. For a manager built with the titleProvider option, createTitleProvider(options) is the provider alone:

import { AparteConversationManager, type AparteStorageAdapter } from '@aparte/core';
import { loadTitler } from '@aparte/titler-latin';
import { createTitleProvider } from '@aparte/plugin-titler';

declare const adapter: AparteStorageAdapter;         // your storage adapter
const manager = new AparteConversationManager(adapter, {
    titleProvider: createTitleProvider({ titler: loadTitler, budget: 4 }),
});

Which model

Package	Languages	Size
@aparte/titler-latin	en, fr, es, de, pt, it, nl, pl, sv, da, fi, cs, ro, no, hu, hr, lt	133 KB
@aparte/titler-latin-mini	the same 17, smaller vocabulary	96 KB
@aparte/titler-efigsp	en, fr, es, de, pt, it	77 KB
@aparte/titler + one .bin	one language	40 KB

Each bundled package ships its model file beside the runtime; a bundler copies it as an asset, and the page fetches it from your own origin. The runtime alone, @aparte/titler, reads any file from the model repository:

import type { AparteConversationManager } from '@aparte/core';
import { loadTitler } from '@aparte/titler';
import { setupTitler } from '@aparte/plugin-titler';

declare const manager: AparteConversationManager;
const titler = await loadTitler(fetch('/models/titler-v1-fr-int3.bin').then((r) => r.arrayBuffer()));
setupTitler(manager, { titler });

The model is extractive: it copies words, it does not rephrase. “Can you explain how photosynthesis works in plants?” becomes explain photosynthesis works plants — the subject, in the message’s own words, which is what a sidebar needs. Try it on the model’s page, where the numbers behind it are laid out.